For this reason, I don't think there is an EPSG code for this projection, which is not surprising given that GRS80 is a fairly outdated CRS (it was soon replaced by the famous WGS84).

EDIT: I tried to load the same file in QGIS, which automatically detected the CRS as EPSG:4258 (which is actually longlat ETRS89). The full description is +proj=longlat +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +no_defs.